runTransformOnResource

This is intended to be used if you have a workspace file
that you want to load as the transformation input. This is the closest thing
to running the transform like the UI. (The UI does is slightly differently
in order to get the console hooked up, etc.... The runTransformOnXXX methods
do not hook into the console).

runTransformOnObject

This method is intended to be used if you have your model already
loaded in memory. This would likely be the case if you have a GMF-created
editor, and you are adding an action to the editor to transform this model
into something else via a JET transform.

runTransformOnString

This method takes a model (typically an XML document) as
a string, and run the transformation against it. As with
runTransformOnObject, if you are using the org.eclipse.jet.resource
variables in you transform, you will have to set them manually.

Tips

There are two 'tricks' to using runTransformOnObject and runTransformOnString.

1) For runTransformOnObject, you must pass an Object that represents the in-memory model. If your
EMF model was generated directly from ECore, pass in the EMF Resource
object. If you EMF model was generated from an XSD Schema, pass in the
instanced of the generated DocumentRoot class.

2) The predefined JET variables for the form org.eclipse.jet.resource.* are not set, because no Eclipse resource was processed during model loading. This will
usually cause some grief with at least the default ws:file tag that
generates a dump of your input model, as it uses
$org.eclipse.jet.resource.project.name. You can pass a Map of variable names
to variable values to an overload of runTransformOnXXX.